                [:nav.home-nav {:class (concat
                                        (when (:header-logo-visible state) ["logo-visible"])
                                        (when (:header-cta-visible state) ["cta-visible"])
-                                       (when (:header-bkg-visible state) ["bkg-visible"]))}
+                                       (when (:header-bkg-visible state) ["bkg-visible"])
+                                       (when (:header-cta-invisible state) ["cta-invisible"])
+                                       (when (:header-bkg-invisible state) ["bkg-invisible"]))}
                 [:a.promo "What is Continuous Integration?"]
                 [:a.login "Log In"]
                 (om/build drawings/logo-circleci app)

                 [:div.drawing]
                 [:div.drawing]
                 (om/build drawings/drawing-build app)]]
               [:section.home-epilog
                [:a.home-action {:role "button"}
                 "Sign Up Free"]
                [:div.home-cover]
                [:div.home-top-shelf]

  (let [logo (om/get-node owner "center-logo")
        cta (om/get-node owner "cta")
        nav-bkg (om/get-node owner "nav-bkg")
        no-cta (om/get-node owner "no-cta")
        nav-no-bkg (om/get-node owner "nav-no-bkg")
        vh (.-height (goog.style/getSize nav-bkg))
        scroll-callback #(do
                           (om/set-state! owner [:header-logo-visible] (neg? (.-bottom (.getBoundingClientRect logo))))
                           (om/set-state! owner [:header-cta-visible] (neg? (.-bottom (.getBoundingClientRect cta))))
                           (om/set-state! owner [:header-bkg-visible] (< (.-bottom (.getBoundingClientRect nav-bkg)) 70))
                           (om/set-state! owner [:header-cta-invisible] (< (.-top (.getBoundingClientRect no-cta)) vh))
                           (om/set-state! owner [:header-bkg-invisible] (< (.-top (.getBoundingClientRect nav-no-bkg)) 70)))]
    (om/set-state! owner [:browser-resize-key]
                   (goog.events/listen
                    (sel1 (om/get-shared owner [:target]) ".app-main")
